Mechanisms for binding bales of crop materials or other substances with strands of twine or wire are well known in the art. One type of such mechanism is often referred to as a “Deering” knotter and is disclosed, for example, in U.S. Pat. No. 4,735,446. Another type of mechanism is sometimes referred to as a “McCormick” bowtie knotter such as disclosed, for example, in U.S. Pat. No. 3,101,963. An example of a wire twister mechanism is disclosed in U.S. Pat. No. 3,202,087. Double knotter machines, wherein each loop around the bale has a pair of knots that join together two end-to-end segments of the strand, have also been very popular, particularly in connection with large square balers that produce large, heavy, dense bales. One example of such a double knotter is disclosed in U.S. Pat. No. 4,142,746 assigned to the assignee of the present invention.
The present invention provides principles that may be advantageously applied to all known types of knotting mechanisms, including but not limited to Deering knotters, McCormick bowtie knotters, wire twisters, and double knotters. Whereas prior devices have relied upon complex mechanical drive and clutch systems deriving their power from the main drive train of the baler and mechanical means for triggering the knotting cycle, the present invention largely eliminates such machinery and provides various electric, hydraulic or pneumatic motors for the knotter components that are controlled by an electronic control system. While individual components of the knotter mechanism, such as strand holders, knot formers, knot strippers, strand fingers, tucker fingers, wire twisters and the like may remain substantially unchanged from prior designs, the means for driving and controlling such components are new in accordance with the principles of the present invention.